PSI - Issue 71

Nisha Thakur et al. / Procedia Structural Integrity 71 (2025) 233–240

238

It was observed that the average reduction in lateral displacement of diagonal bracings, X-type (intersected) bracings, K-type bracings and X-type bracings are 64.98%, 73.33%, 69.52%, and 73.33% respectively. It was found that the maximum lateral displacement is decreased due to bracing systems in buildings. Also, it is observed that when X-type (intersected) or X-type bracing is provided in the building, it reduces lateral displacement to a large extent. 3.2. Maximum Axial Force and Bending Moment in columns: For seismic analysis, Table 3 to Table 5 shows the maximum axial force, shear force, and bending moment respectively, in columns of building frames with unbraced and braced systems. These results are obtained in all 3 directions of a building. It is observed that though in some situations axial forces are marginally increasing but when the reduction of shear force and bending moments are observed, the differences in the values of shear force and bending moments are very large. Table 3 shows the maximum axial force in column for different types of bracing systems of a building frame. It was observed that the average marginal increase in the axial force of diagonal bracings, X-type (intersected) bracings, and X-type bracings are 1.94%, 5.67%, and 5.63%, respectively whereas for K-type bracings there was reduction in axial force of 6.18%. It was found that the axial force is maximum when X-type (intersected) bracings, and X-type bracings are provided as compared to other types of bracings or without bracings. The increased axial force may further lead to increased column loads which require redesigning the foundation to avoid frame instability but in the present study, the marginal increase is not a point of concern as RC columns are strong in compression.

Table 3: Max. Axial Force in Column in KN

Seismic Load on various types of bracings Not provided Diagonal X-type (intersected) K-type

Floor

X-type

4 th 3 rd 2 nd

91.58

93.50

83.37

79.55

83.38

243.60 417.78 605.89 794.89

234.76 398.78 632.38 885.45

234.12 446.64 696.75 948.19

205.93 234.24 376.92 446.80 604.10 695.10 856.79 948.24

1 st

0

Table 4 shows the maximum shear force in columns for different types of bracing systems of a building frame. It was observed that the average reduction in maximum shear of diagonal bracings, X-type (intersected) bracings, K-type bracings and X-type bracings are 54.64%, 67.23%, 51.16%, and 67.20%, respectively. It was found that the maximum shear force is decreased when X-type (intersected) or X-type bracing are provided. The decrease in shear force reduces the risk of shear failure, increases structural stability and reduces the damage to non-structural elements like ceilings, partitions, etc. in seismic-prone areas.

Table 4: Max. Shear Force in Column in KN

Seismic Load on various types of bracings Not provided Diagonal X-type (intersected) K-type

Floor

X-type

4th 3rd 2nd

23.15 39.80 51.87 56.15 51.90

11.50 15.92 18.71 17.97 35.83

11.45 11.88 12.84 10.65 21.19

14.32 18.76 21.17 21.61 29.02

11.49 11.88 12.85 10.62 21.18

1st

0

Table 5 shows the maximum bending moment in column for different types of bracing systems of a building frame. It was observed that the average reduction in maximum bending moment of diagonal bracings, X-type (intersected) bracings, K-type bracings and X-type bracings are 58.90%, 71.14%, 58.10%, and 74.76%, respectively. It was found that the maximum bending moment is decreased when X-type of bracing is provided. The decrease in bending moment reduces the risk of flexural failure, increases structural stability and reduces the deflections ensuring the structure remains within the acceptable limits.